2,000 years ago the Jews that Jesus was talking too that day thought he literally meant eat him. That is why they walked away and that is why Jesus said it was a hard saying.
Well if I was calvinist, I would say the hard saying was that no one can come to the father unless drawn.
But I don't believe that's it.
And it wasn't JUST believing in him. It was WHAT he told them to believe.
What had Jesus said that they considered a “hard saying” (v.60)? Catholics say they were speaking of when He said they had to eat his flesh and drink His blood (v.56), but the Jesus' answer indicates otherwise. When He asked, “What and if ye shall see the Son of man ascend up where He was before?” (v.62), it shows they were having trouble believing when He said
He came down from heaven (v.58). He was saying, “If you see me go back to heaven where I came from, will you believe I came down from heaven?” They knew He was born in Bethlehem, and since they knew souls did not pre-exist, they knew He was saying
He was God. And
that’s what they found to be “a hard saying.” These disciples were following only because they tasted the bread he multiplied (8:26). Announcing He was God was too much for them. John once again emphasizes the Lord’s deity when he says He “knew in Himself” what they were saying (v.61)
When he said " eat my flesh" they flat out sneered at him.
They said, “Is this not Jesus, the son of Joseph, whose father and mother we know? How can he now say, ‘I came down from heaven’?”
It wasn't just the bread metaphor, although they may have been confused by it.
He put himself on the same level as Yahweh! To the Jews this was blasphemy. It was too much for those following because they thought he was going to set up an Earthly kingdom and defeat the Romans, and hey, maybe pass out the free bread that he could create every day!